Does a patient-based version of the Constant-Murley score produce similar and reliable results, as compared to the original clinician-based Constant-Murley score?

SUMMARY

Rationale: The Constant-Murley (CM) score is one of the most commonly used scoring systems for shoulder arthroplasty, combining assessment by the clinician (range of movement (ROM) and strength) and by the patient (pain and activities of daily living (ADL)).

A patient-based CM score was developed in the United Kingdom (UK) and tested for its reliability in a population of patients with mixed diagnoses, not including shoulder arthroplasty.
However, both scores have not been evaluated in a Dutch setting and there are varied reports regarding the reliability of the CM score, justifying further analysis alongside translation and validation of both scores in Dutch. Rating scale analysis with item response theory (IRT) modeling can evaluate the performance of items and overall scores more thoroughly.

Objective: To assess the validity, reproducibility and performance of the clinician-based and patient-based CM scores, and to determine the smallest detectable change (SDC) and minimal clinically important difference (MCID) of both CM scores in a population of patients undergoing shoulder arthroplasty.

Study design: Clinimetric study

Study population: Patients scheduled to undergo shoulder arthroplasty, aged 18 years and older.

Main study parameters/endpoints: The main study parameters are the construct validity, reproducibility (exact and adjacent agreement for ordinal scores, standard error of measurement (SEM) and smallest detectable change (SDC) for continuous scores) and performance of the separate items and overall scores assessed with IRT modeling.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: We expect no risks associated with participation, due to the nature of the study (filling out questionnaires and undergoing physical assessment in the same manner as routine care). The extra burden placed on patients will consist of two extra visits to the orthopaedic surgeon (T1 and T2) for administration of the clinician-based score, completing four extra questionnaires at baseline, completing two questionnaires at T1 and completing seven questionnaires at T2.



The MEC declared that ethical approval for this study is not necessary.

To evaluate the validity, reproducibility and scale functioning of the Dutch clinician-based Constant-Murley (CM) score and of a Dutch patient-derived Constant-Murley score in patients with shoulder arthroplasty.

To define the smallest detectable change (SDC) and minimal important change (MIC) of both the clinician-derived and patient-derived CM score in patients with shoulder arthroplasty

T0: within 6 months pre-operatively

T1: 2 weeks after T0

T2: 6 months post-operatively

The treating orthopaedic surgeon will perform the clinician-based CM score during a clinic visit. All other questionnaires will be completed by the patients, either on paper or digital (according to patient preference)

T0: clinician-based CM score, patient-based CM score, Oxford Shoulder Score (OSS), Simple Shoulder Test (SST), Numeric Rating Scale (NRS), EuroQoL-5D (EQ-5D)



T1: clinician-based CM score, patient-based CM score, anchorquestion

T2: clinician-based CM score, patient-based CM score, Oxford Shoulder Score (OSS), Simple Shoulder Test (SST), Numeric Rating Scale (NRS), EuroQoL-5D (EQ-5D), anchorquestion